The invention pertains to a photometer microscope with an apparatus for the microphotometer scanning of fine specimen-structures, which, in the ray-path between the objective and the photometer-part, exhibits an internal focusing lens
Photometer microscopes with an apparatus for the microphotometer scanning of small specimen-structures are used for the study of diverse objects. One field of utilization, for instance, is a study of chromosomes, inasmuch as for some years now, methods exist with which it became possible to produce on chromosomes transverse stripes of different color intensity. This coloration makes it possible to reliably distinguish the chromosome-pairs from each other, and to correspondingly classify them.
The differences in the color intensity of the transverse stripes can be recognized with the naked eye only with great difficulty. For this reason photometer microscopes are used, which can measure and graphically record the different color intensities. For such an evaluation, it is required that the object to be studied be moved for microphotometer scanning, in order to be able to scan point by point the interesting parts of the object specimen in corresponding time sequence. The measured values are stored in a computer during scanning at the conclusion of the scanning, the information about the objects are computer evaluated and reported.
To produce the necessary relative movement, different devices have been used. In general, the procedure is to secure the object on a motor driven stage. The motors can be either direct current motors which are controlled by a joy-stick, or stepping motors can be used. In the first case, one gets a continuous, infinitely adjustable movement while in the second case, the step magnitude is not adjustable. With tasks with stepping motors, a minimal step size of 0.5 um is possible which is not sufficiently small for the study of chromosomes, because a step of 0.1 um is required. Consequently, work can only be done with a movable stage, if realtively coarse objects are to be studied.
Despite the use of a movable stage, in order to make possible a finer scanning, it is also known to electronically increase the number of measurements during one step of the stage. For example, if four measurements are taken during an 0.5 um step, effective distance is reduced to about 0.125 um. This procedure, can only be applied in one direction. Since the time available for a measurement by this system is naturally very short, evaluation of the results is difficult.
To overcome these problems the chromosomes or the like are first photographed and then evaluated from the photos thus obtained, which are larger than the originals, by the photometer microscope. It is obvious that this procedure also is not satisfactory, as it significantly increases time and errors can creep in, for instance, through defects of the photographic emulsion.
It is likewise known how to provide in the ray-path of the microscope between the objective and the photometer-part, an internal focusing lens, which moves the image past the measuring diaphragm (restrictor). This Method has the advantage that relatively small steps can be achieved, inasmuch as the already magnified image is now moved, hence the magnification factor of the objective can remain neglected. A disadvantage of the known arrangement, however is, above all, that through the additional lens, the ray-path of the microscope becomes altered, so that the microscope must be modified to accept the additional lens. Consequently, the known arrangement cannot find acceptance as an attachment for microscopes. Furthermore, it is proposed to move the lens by hand using a pantograph-like device. This has the substantial disadvantage that small, uniform movement cannot be achieved although such movement is not required because measurement takes place as a function of the position of the pantograph. Naturally, the disadvantage arises from this, that no continuous scanning of the specimen is possible, but only discrete areas, separated from each other, can be covered in any given case.
Finally, it is already known how to undertake an image-shift by optical means in the image field, for which purpose glass wedges or prisms, or rotatable or displaceable deflecting mirrors, operating opposite each other, are provided. Here also, however, the problem arises that the scanning steps, in general, do not become as fine as they are required to be. Additionally, devices having several prisms or deflecting mirrors are of a projecting nature so that only with difficulty if at all can they be brought into the microscope tube, and above all, they are not suitable for utilization as an attachment.